June 25, 2013

Danish Chemists Use Graphene To Create Molecular Integrated Circuit

Electronic components built from single molecules using chemical synthesis could pave the way for smaller, faster and more green and sustainable electronic devices. Now for the first time, a transistor made from just one molecular monolayer has been made to work where it really counts. On a computer chip.

Molecular electronics are a long-proposed aim to use the basic building blocks of electronics, individual molecules to form circuits. A reliable method for testing these molecular components has remained elusive however.

Now a joint research team comprising chemists and physicists from the Department of Chemistry Nano-Science Center at the University of Copenhagen and the Chinese Academy of Sciences in Beijing has developed a graphene-based chip whose initial application could be testing the molecular chips researchers envision.

Kasper Nørgaard, an associate professor of chemistry at the University of Copenhagen, believes that the first applications for the graphene-based chip will be in testing future molecular electronics, the chip itself represents a first step towards integrated molecular circuits.

"What we have shown for the first time is that it’s possible to integrate a functional component on a graphene chip," says Nørgaard. "I honestly feel this is front page news.”

“The difference between this work and “graphene transistors” in general is that we use a molecular monolayer as the active (switchable) layer between a graphene electrode and a gold electrode, i.e. we are working in the field of molecular electronics in combination with graphene electronics,” Nørgaard explained to IEEE Spectrum's Dexter Johnson.

“The advantage of this molecular approach is that molecules can be tailor-made to provide a variety of interesting functions with tunable properties—in this case the ability to switch conductance as a function of light irradiation.”

The molecular computer chip is a sandwich built with one layer of gold, one of molecular components and one of the extremely thin carbon material graphene. The molecular transistor in the sandwich is switched on and of using a light impulse so one of the peculiar properties of graphene is highly useful. Even though graphene is made of carbon, it’s almost completely translucent.

This new chip should bring an entirely new level of precision to IC formation by enabling the precise placement of the molecules rather than essentially just pouring them out of a beaker. With this chip, molecular wires, diodes, and contacts can now be tested quickly to determine their characteristics.

“We’ve made a design, that’ll hold many different types of molecule” he says and goes on: “Because the graphene scaffold is closer to real chip design it does make it easier to test components, but of course it’s also a step on the road to making a real integrated circuit using molecular components. And we must not lose sight of the fact that molecular components do have to end up in an integrated circuit, if they are going to be any use at all in real life”.